Bipedal robots which have in recent years been proposed for practical use by the present applicant and others and which have been known in general are basically human-shaped robots. Like human beings, they have two legs extending from a hip at the lower end of an upper body (torso), and two arms extending from shoulders on the left and right opposite sides of the upper body.
Robots which carry an electric energy storage device as a power supply for operating the robots also have an electronic circuit unit (controller) that is usually mounted on an upper body of the robot for controlling operation of the electric energy storage device and the robot.
For a bipedal robot to be able to carry out various works in a variety of environments, it is desirable that the tip ends of the arms of the robot reach as far a position as possible.
If arms are elongated, then the tip ends of the arms can reach a far position. However, if arms are too elongated, then the robot tends to lose the stability of its attitude when the arms are extended and perform some work, and finds it difficult to work with the arms at a location close to the robot.
When a conventional bipedal robot is to grip, with its arms, an object that is present laterally of the robot, the robot basically moves the legs to direct the robot in its entirety to face the object. In environments where the footing is unstable or limited to a small area, however, it may be difficult to move the legs to change the direction of the robot in its entirety. In those environments, the robot practically fails to grip the object.
The present invention has been made in view of the above background. It is an object of the present invention to provide a bipedal robot which is capable of increasing its working capability without impairing the stability of the attitude when the robot works.
Another object of the present invention is to provide a bipedal robot whose maintenance can easily be carried out.